Strobe Pre-Emission for Face Detection in Low Light
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Solution Overview
Problem
Modern digital photographing apparatuses often produce poor-quality images of people due to inconsistent strobe light, resulting in faces appearing too dark or too light, as existing technologies fail to accurately determine and adjust strobe light strength based on the subject's face region.
Innovation Solution
A photographing control method and apparatus that involves pre-emission of the strobe to obtain image data, detect the face region, and calculate the main emission based on the detected face region to adjust the strobe light accordingly, ensuring optimal illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strobe light is emitted without pre-emission and face detection, then the photographing process is simple and fast, but the face region cannot be accurately detected and the strobe light strength cannot be adjusted, resulting in poor image quality
Solution Approach 1:
The patent applies preliminary action by performing pre-emission of the strobe light before the main photographing operation. This pre-emission enables the system to capture image data of the subject's face region under controlled lighting conditions, allowing accurate face detection and subsequent adjustment of strobe light strength for optimal image quality.
Solution Approach 2:
The patent implements feedback by detecting the face region based on image data obtained during pre-emission, then using this detection result to calculate and adjust the main emission strength of the strobe light. This closed-loop feedback ensures that the strobe light strength is optimized based on actual face region characteristics.
2Manufacturing precision
If pre-emission is performed to obtain image data and detect face region, then the strobe light strength can be accurately adjusted, but the photographing time is extended
Solution Approach 1:
The pre-emission is performed as a preliminary action before the main photographing operation, allowing the system to pre-process image data acquisition and face detection. This enables the main emission to be optimized based on pre-obtained information, improving light strength adjustment accuracy.
Solution Approach 2:
The patent uses partial action by performing pre-emission with controlled duration and intensity sufficient to obtain adequate image data for face detection, but not excessively long or intense to cause unnecessary time delay. The pre-emission is optimized to achieve the minimum necessary for accurate face region detection.
3Measurement precision
If face detection is performed on live view image, then the face region can be detected, but the detection accuracy is insufficient when face brightness is low or high
Solution Approach 1:
The patent performs pre-emission as a preliminary action to illuminate the subject's face region before detection. This pre-illumination ensures that the face region is adequately lit during image data acquisition, improving detection accuracy regardless of ambient lighting conditions.
Solution Approach 2:
The patent changes the lighting parameters by controlling the pre-emission strobe light to provide optimal illumination for face detection. By adjusting the pre-emission light strength and duration, the system creates ideal lighting conditions for accurate face region detection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases the probability of detecting the face and produces well-exposed images by accurately determining and adjusting the strobe light strength, addressing the issue of inconsistent image quality.
Implementation Method 1
a strobe light which emits light that is reflected by the person and back to the photographing apparatus
Data Source
AI summary
Provided are a photographing control method and apparatus. The photographing control method includes: obtaining image data from a subject during pre-emission of a strobe, detecting a face region of the subject based on the obtained image data, and performing a calculation for main emission based on the detected face region and controlling main emission of the strobe. Accordingly, even when it is difficult to detect a face because of low brightness at the position of the face, the probability of detecting the face can be increased and an appropriately exposed image can be obtained.